It is well known to provide buccal tubes for anchoring archwires and applying torque during orthodontic treatment. During orthodontic treatment an archwire will have sliding movement relative to the tubes.
Heretofore, it has also been known to provide rectangular archwire for effecting torque control between the archwire and the buccal tubes. Where torque was desired, the lumens in the tubes were configured such that the sliding friction between the archwire and the tubes could affect treatment time. Some heretofore known tubes that control torque and provide some relief around portions of the archwire include U.S. Pat. Nos. 4,781,582; 5,057,012, and 5,727,941. However, treatment time is at least partially dependent on the level of sliding friction between the archwire and the tubes. A lower level of sliding friction enhances and shortens the treatment time.